Bad 90 rotation from
This happens when we don't set the 'forward' and 'up' directions properly when exporting and importing.

When you click export to .obj in blender, you will be shown a screen to select the name of the .obj and output folder. Along with it, on the left of the screen, you will find the settings for export (if you don't see this panel, press 'T'). In those settings, by default, you can find the forward and upward directions as shown below.



When exporting, these directions are supposed to be the directions of the 3D program from which we are exporting. In our case Blender itself. So set it as follows. Because in blender, Z is the up direction and Y is the forward direction.Why? Because of what Blender shows as front view and top view.



Similarly, when we are importing, these directions specify the up and forward directions of the 3D program, from which the .obj file is exported. In your case, its blender again. So set it again to Y Forward and Z up.

Now, you won't get any wrong transform values.